Function SCIPbranchVarValNary 

pub unsafe extern "C" fn SCIPbranchVarValNary(
    scip: *mut SCIP,
    var: *mut SCIP_VAR,
    val: f64,
    n: c_int,
    minwidth: f64,
    widthfactor: f64,
    nchildren: *mut c_int,
) -> SCIP_RETCODE

n-ary branching on a variable x using a given value

Branches on variable x such that up to n/2 children are created on each side of the usual branching value. The branching value is selected as in SCIPbranchVarVal(). The parameters minwidth and widthfactor determine the domain width of the branching variable in the child nodes. If n is odd, one child with domain width ‘width’ and having the branching value in the middle is created. Otherwise, two children with domain width ‘width’ and being left and right of the branching value are created. Next further nodes to the left and right are created, where width is multiplied by widthfactor with increasing distance from the first nodes. The initial width is calculated such that n/2 nodes are created to the left and to the right of the branching value. If this value is below minwidth, the initial width is set to minwidth, which may result in creating less than n nodes.

Giving a large value for widthfactor results in creating children with small domain when close to the branching value and large domain when closer to the current variable bounds. That is, setting widthfactor to a very large value and n to 3 results in a ternary branching where the branching variable is mostly fixed in the middle child. Setting widthfactor to 1.0 results in children where the branching variable always has the same domain width (except for one child if the branching value is not in the middle).

@return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref SCIP_Retcode “SCIP_RETCODE” for a complete list of error codes.

@pre This method can be called if @p scip is in one of the following stages: - \ref SCIP_STAGE_SOLVING

See \ref SCIP_Stage “SCIP_STAGE” for a complete list of all possible solving stages.